[TIMOB-1830] Android: FC when trying to open lightweight window with Mapview a second time

Simple failcase app.js:

Titanium.UI.setBackgroundColor('#000');
var win = Titanium.UI.createWindow({  
    title:'Map Test', backgroundColor:'#fff',
    fullscreen: true, exitOnClose: true
});

var open = Ti.UI.createButton({title: 'Open mapview window'});
open.addEventListener('click', function(){
    var w2 = Ti.UI.createWindow({title: 'Map View', backgroundColor: 'green'});
    var mapview = Titanium.Map.createView({
        mapType: Titanium.Map.STANDARD_TYPE,
        region: {latitude:33.74511, longitude:-84.38993, 
                latitudeDelta:0.01, longitudeDelta:0.01},
        top: 0, left: 0, right: 0, height: 300
    });
    w2.add(mapview);
    var close = Ti.UI.createButton({title: 'close', top: 305});
    close.addEventListener('click', function(){ w2.close(); });
    w2.add(close);
    w2.open();
});
win.add(open);

win.open();

The map activity only gets destroyed when the "parent" activity gets destroyed. Since lightweight windows don't have their own activities, destroy doesn't occur. If you try to the same or another window with a mapview, it will therefore fail.

We need a way to get that map activity destroyed even when the host window is lightweight. In the past we've told some users about an undocumented hack, calling mapview.OnDestroy. But we shouldn't do that as it's not cross-platform and may be unavailable with new Kroll.